"Consider the KR wing structure (below the skin) and imagine dividing the top surface of the wing into 1' x 1' squares and screwing a cup hook into each square. Turn it over and hang 38 lbs on each of the 80 or so cup hooks."
Hello Net This is long, if you have a KR to work on, repair , or fly, don't waste your time on this!! It's 29 and snowing here in SE Michigan. For me it's a good day to learn something new. About this G loading of a KR wing, I guess I really would like to learn more, especially since my KR is over 20 years old. It doesn't have wing skins, just the one's I made. I thought that in flight the air traveling over the curved upper surface caused low pressure on the bottom surface and that's what caused lift. As a pilot I learned that in a climbing turn, that one wing is closer to stall then the other, and also that in a pull up, the wing panels transfer the lifting force, what ever the G's to the spars and in particular for the KR, the attach fittings. Such that in an overloaded +G condition the force acting on the wing would be downward as the fuselage trys to pull up. In this situation I always thought the forces were pushing down on the top of the skin. Following that in a -G condition, the wing would try to continue to fly with lift from the bottom while the fuselage trys to force downward, causing the wings fold in failure. I would think that as the spar bends, that the adhesion of the skin to the spar would act to prevent the bending. I can see where gluing the wing skins really good is important. I can't see where the force to lift the skin from the spar comes from. As you will note, I present this as things I would like to learn, since I don't have much aerodynamic training. In a practical since I'm not sure that if I attached a 38 pound weight on the unsupported wing skin, say the space between the spars and ribs, that the thing would not drop through. I'm positive that my original wing covering of one layer of Dynel would not. I have seen pictures and read articles about load testing of wings where nearly a ton a sand bags have been stacked on the aircraft wing to simulate the G loading and read of some that have continued to stack till failure. There tests looked for the destruction of the wing as whole. Over the years the only non straight and level flying that I do is the occasional high speed pass with a pull up. I have no idea at what amount of G's. Orma Southfield, MI N110LR celebrating 20 years Flying, flying and more flying http://www.kr-2.aviation-mechanics.com/ Do not Archive
